The present invention relates to a food material heating mechanism for heating food materials such as hamburger buns. Fast-food restaurants sell various types of hamburgers and sandwiches preparing them according to the orders of customers. In order to prepare ordered items quickly and sell them on the spot, buns are generally heated as follows.
A bun is cut into two portions; a lower portion (hereinafter referred to as a "heel" and an upper portion (hereinafter referred to as a "crown"). A heating plate, which applies heat to heels and crowns, comes into contact with a cut surface of a heel or a crown and heats it for a specific time to raise the inside temperature to about 80.degree. C. At this stage, the temperature of the heating plate is set relatively high (about 230.degree. C.), so that a crusty baked layer forms on the cut surface. This crusty layer adds to the flavor, prevents sauces added to the surface from soaking into the heel or crown, and keeps the heated heel or crown crisp.
In general, it takes longer to heat the inside of a heel or crown than it does to obtain a crusty layer on the cut surface. By the time the inside is fully heated, the cut surface is overcooked by the heating plate. This can cause the cut surface to become burned or too dry with a resulting deterioration in taste. This is a problem in the food preparation industry.